Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual foi a presença em 11 de setembro de 1988?
 ###Tabelas: CREATE TABLE pool_2 (pool_2_id AUTO_INCREMENT PRIMARY KEY, Team VARCHAR, Tries for VARCHAR, Tries against VARCHAR, Try diff VARCHAR, Points for VARCHAR, Points against VARCHAR, Points diff VARCHAR) CREATE TABLE 1990s (1990s_id AUTO_INCREMENT PRIMARY KEY, Year INT, Date VARCHAR, Location VARCHAR, Score VARCHAR, Result VARCHAR) CREATE TABLE list_of_iranian_banks (list_of_iranian_banks_id AUTO_INCREMENT PRIMARY KEY, Bank VARCHAR, Score (Iran) INT, Score (Global) INT, Banking Power/Capital Base ($ Million) INT, Banking Power/Capital Base (% Change) VARCHAR, Total Assets ($ Million) INT, Total Assets (Score) INT, Total Assets (% Change) VARCHAR, Credibility/Capital to Assets Ratio (%) INT, Credibility/Capital to Assets Ratio (Score) INT, Performance/Return on Capital (%) INT, Performance/Return on Capital (Score) INT, Return on Assets (%) INT, Return on Assets (Score) INT) CREATE TABLE list_of_housing_and_construction_ministers (list_of_housing_and_construction_ministers_id AUTO_INCREMENT PRIMARY KEY, Minister VARCHAR, Party VARCHAR, Governments VARCHAR, Term start VARCHAR, Term end VARCHAR) CREATE TABLE schedule (schedule_id AUTO_INCREMENT PRIMARY KEY, Week INT, Date VARCHAR, Opponent VARCHAR, Result VARCHAR, Attendance INT)  
SELECT AVG Attendance FROM schedule WHERE Date = september 11, 1988